To investigate the role of the sacculus in vestibular and auditory function in animals and to correlate the linear acceleration findings in animals (controlled vertical linear acceleration, counter-rotation centrifuge and horizontal rotation) with those in humans. This study is an expansion of those sacculus studies of Fernandez and Kohut using methods of controlled vertical linear acceleration and dual electrode recordings of labyrinthine responses to sound. It includes the study of saccular function, its interrelation with cochlear and vestibular apparatus and the peculiarities of saccular innervation in animals and man. Objectives and methods: 1. To determine the stimulus variables and responses to linear acceleration in experimentally altered cats and naturally occurring altered humans. (Cochleo-saccular degeneration is present in the colony of white cats available to this project; Scheibe type human abnormaities are available in the clinic population.) 2. To determine the auditory function of the sacculus: a. Dual electrode recordings with phase shift on sacculus puncture in animals and man (humans needing labyrinthectomy for reasons of disease).